MySQL 5.5 Reference Manual

2.3.3.3. Removing MySQL When Installed from the MSI Package

To uninstall a MySQL where you have used the MSI packages, you
must use the Add/Remove Programs tool
within Control Panel. To do this:

Right-click the start menu and choose
Control Panel.

If the Control Panel is set to category mode (you will see
Pick a category at the top of the
Control Panel window), double-click
Add or Remove Programs. If the Control
is set to classic mode, double-click the Add or
Remove Programs icon.

Find MySQL in the list of installed software. MySQL Server
is installed against major version numbers (MySQL
5.1, MySQL 5.5, etc.). Select the
version that you want to remove and click
Remove.

You will be prompted to confirm the removal. Click
Yes to remove MySQL.

When MySQL is removed using this method, only the installed
components are removed. Any database information (including the
tables and data), import or export files, log files, and binary
logs produced during execution are kept in their configured
location.

If you try to install MySQL again the information will be
retained and you will be prompted to enter the password
configured with the original installation.

If you want to delete MySQL completely:

Delete the associated data directory. On Windows XP and
Windows Server 2003, the default data directory is the
configured AppData directory, which is
C:\Documents and Settings\All Users\Application
Data\MySQL by default.